A known type of slide door device is disclosed in Japanese Patent Laid-Open Publication No. Hei 10(1998)-18708, published without examination. This slide door device includes a slide door which exposes and covers an opening area formed in the lateral side of a vehicle-body such that the slide door is moved along a center guide rail extending in the vehicle-lengthwise direction. The slide door device also includes a driving mechanism having an electric motor as a driving source and an output drum, and an endless wire cable wound on the output drum and guided through the center guide rail such that the wire extends from the rear end to the front end of the center guide rail and is turned back via a guide pulley connected to the rear end of the center guide rail so as to be connected to the slide door.
In this known slide door device, the opening and closing movement of the slide door to cover and uncover the opening area in the vehicle body is established by movements of the wire cable along the center guide rail in one direction and the other direction when the output drum is rotated by the electric motor in one direction and the other direction, respectively.
Generally speaking, the slide door is positioned at the rear side of the opening area when the slide door is in the opened condition such that the slide door is on the exterior surface of the vehicle body, and is positioned in the opening area when the sliding door is in the closed condition such that the slide door is coplanar with the exterior surface of the vehicle body. To establish such conditions of the slide door, the center guide rail is bent at its front end in the vehicle lengthwise direction toward the interior of the vehicle.
In the known slide door device, a pulley is provided at the vehicle lengthwise front end of the center guide for guiding the wire. The resulting projection of the pulley toward the interior of the vehicle becomes larger and this causes a narrowing of the interior space of the vehicle, thereby disturbing the comfort and the ease with which the passengers can get into and out of the vehicle.
In addition the guide pulley is subject to receive a force larger than the driving force applied to the wire cable while the slide door is being moved. As a result, strengthening of the support structure of the pulley to the center guide rail is required so as not to be overcome by the force. This means that the thickness of a metal plate of each element of the structure has to be increased and a reinforcing member has to be added to the support structure, and so the total weight of the slide door device is increased as are the manufacturing costs.
A need thus exists for a slide door device that is not susceptible to the same drawbacks as those mentioned above.
It would thus be desirable to provide a slide door device for an automotive vehicle which is relatively light-weight, relatively economical to manufacture, and relatively compact in size.